JP5940992B2 - Exhaust gas purification catalyst - Google Patents
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- JP5940992B2 JP5940992B2 JP2013014477A JP2013014477A JP5940992B2 JP 5940992 B2 JP5940992 B2 JP 5940992B2 JP 2013014477 A JP2013014477 A JP 2013014477A JP 2013014477 A JP2013014477 A JP 2013014477A JP 5940992 B2 JP5940992 B2 JP 5940992B2
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- 239000003054 catalyst Substances 0.000 title claims description 151
- 238000000746 purification Methods 0.000 title claims description 46
- 239000000463 material Substances 0.000 claims description 33
- 239000000758 substrate Substances 0.000 claims description 24
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 21
- 239000011148 porous material Substances 0.000 claims description 13
- 229910052703 rhodium Inorganic materials 0.000 claims description 13
- 229910052697 platinum Inorganic materials 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 7
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 2
- 239000010941 cobalt Substances 0.000 claims description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 2
- -1 and Co Substances 0.000 claims 1
- 229910000428 cobalt oxide Inorganic materials 0.000 claims 1
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 claims 1
- 239000010410 layer Substances 0.000 description 112
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 53
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 42
- 229910002091 carbon monoxide Inorganic materials 0.000 description 42
- 239000007789 gas Substances 0.000 description 40
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- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 3
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- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 3
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- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
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- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 2
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
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- 238000005275 alloying Methods 0.000 description 1
- HEHRHMRHPUNLIR-UHFFFAOYSA-N aluminum;hydroxy-[hydroxy(oxo)silyl]oxy-oxosilane;lithium Chemical compound [Li].[Al].O[Si](=O)O[Si](O)=O.O[Si](=O)O[Si](O)=O HEHRHMRHPUNLIR-UHFFFAOYSA-N 0.000 description 1
- CNLWCVNCHLKFHK-UHFFFAOYSA-N aluminum;lithium;dioxido(oxo)silane Chemical compound [Li+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O CNLWCVNCHLKFHK-UHFFFAOYSA-N 0.000 description 1
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- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
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- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
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Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Description
本発明は、内燃機関から排出される排気ガスを浄化するために用いることができる排ガス浄化触媒、特に一酸化炭素（ＣＯ）の浄化性能に優れた排ガス浄化触媒に関する。 The present invention relates to an exhaust gas purification catalyst that can be used to purify exhaust gas discharged from an internal combustion engine, and more particularly, to an exhaust gas purification catalyst having excellent carbon monoxide (CO) purification performance.
ガソリンを燃料とする自動車の排気ガス中には、炭化水素（ＨＣ）、一酸化炭素（ＣＯ）、窒素酸化物（ＮＯx）等の有害成分が含まれる。前記炭化水素（ＨＣ）は酸化して水と二酸化炭素に転化させ、前記一酸化炭素（ＣＯ）は酸化して二酸化炭素に転化させ、前記窒素酸化物（ＮＯx）は還元して窒素に転化させ、それぞれの有害成分を触媒で浄化する必要がある。
このような排気ガスを処理するための触媒（以下「排ガス浄化触媒」と称する）として、ＣＯ、ＨＣ及びＮＯｘを酸化還元することができる３元触媒（Three way catalysts：ＴＷＣ）が用いられている。
The exhaust gas of automobiles using gasoline as fuel contains harmful components such as hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). The hydrocarbon (HC) is oxidized and converted into water and carbon dioxide, the carbon monoxide (CO) is oxidized and converted into carbon dioxide, and the nitrogen oxide (NOx) is reduced and converted into nitrogen. It is necessary to purify each harmful component with a catalyst.
As a catalyst for treating such exhaust gas (hereinafter referred to as “exhaust gas purification catalyst”), a three-way catalyst (Three way catalysts: TWC) capable of oxidizing and reducing CO, HC and NOx is used. .
３元触媒としては、高い比表面積を有する耐火性酸化物多孔質体、例えば高い比表面積を有するアルミナ多孔質体に、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）等の貴金属を担持し、これを基材、例えば耐火性セラミック又は金属製ハニカム構造で出来ているモノリス型（ｍｏｎｏｌｉｔｈｉｃ）基材に担持したり、或いは、耐火性粒子に担持したりしたものが知られている。 As the three-way catalyst, a noble metal such as platinum (Pt), palladium (Pd), rhodium (Rh) is supported on a refractory oxide porous body having a high specific surface area, for example, an alumina porous body having a high specific surface area. In addition, it is known that this is supported on a base material, for example, a monolithic base material made of a refractory ceramic or a metal honeycomb structure, or supported on refractory particles.
近年、上記の白金やロジウムがとても高価であるため、製造コストを抑えるために、比較的安価なパラジウムを用いた排気ガス浄化触媒が提案されている(例えば特許文献１など)。
しかし、パラジウムは、排気ガス中の硫化水素(Ｈ2Ｓ)等の硫黄分によって被毒を受け易く、劣化し易いという問題を抱えていた。そこで、触媒層を上下２層とし、下層にパラジウム（Ｐｄ）を含有させることが提案されている。
In recent years, since platinum and rhodium are very expensive, an exhaust gas purification catalyst using relatively inexpensive palladium has been proposed in order to reduce manufacturing costs (for example, Patent Document 1).
However, palladium has a problem that it is easily poisoned and deteriorated by sulfur components such as hydrogen sulfide (H 2 S) in the exhaust gas. Therefore, it has been proposed that the catalyst layer has two upper and lower layers and that the lower layer contains palladium (Pd).
例えば特許文献２には、ハニカム担体上に、触媒貴金属としてパラジウムと、アルミナと、酸素吸蔵材とを含有する触媒層が備えられた排気ガス浄化触媒であって、前記触媒層は、上下２層からなり、前記パラジウムは下層に担持されていると共に、前記ロジウムは上層に担持されていることを特徴とする排気ガス浄化触媒が開示されている。 For example, Patent Document 2 discloses an exhaust gas purification catalyst in which a catalyst layer containing palladium, alumina, and an oxygen storage material as catalyst noble metals is provided on a honeycomb carrier, and the catalyst layers are divided into upper and lower layers. An exhaust gas purifying catalyst is disclosed in which the palladium is supported on the lower layer and the rhodium is supported on the upper layer.
また、特許文献３には、上層のアルミナには白金を担持させ、上層の酸素吸蔵材にはロジウムを担持させ、下層のアルミナにはパラジウムを担持させ、各触媒貴金属をそれぞれ相異なるアルミナ及び酸素吸蔵材に分離して担持させることとなり、異種の触媒貴金属のシンタリング及び合金化を防ぐことができる触媒が開示されている。 In Patent Document 3, platinum is supported on the upper layer alumina, rhodium is supported on the upper oxygen storage material, palladium is supported on the lower layer alumina, and each catalyst noble metal is made of different alumina and oxygen. There has been disclosed a catalyst that can be separated and supported on an occlusion material and prevent sintering and alloying of different kinds of catalyst noble metals.
さらに特許文献４には、担体上に、複数の触媒層が層状に形成されている排気ガス浄化触媒において、最上層の触媒層よりも下層側に位置している所定の触媒層が酸化ニッケルとパラジウムとを含む排気ガス浄化触媒が開示されており、パラジウムの周囲に酸化ニッケルが存在することで、この酸化ニッケルがパラジウムへの毒性物質の接近を妨げるのでパラジウムの被毒が抑制される旨が開示されている。 Further, in Patent Document 4, in an exhaust gas purification catalyst in which a plurality of catalyst layers are formed in layers on a carrier, a predetermined catalyst layer positioned on a lower layer side than the uppermost catalyst layer is nickel oxide. An exhaust gas purifying catalyst containing palladium is disclosed, and the presence of nickel oxide around palladium prevents the poisoning of palladium because this nickel oxide prevents access of toxic substances to palladium. It is disclosed.
近年のＣＯ２排出量低減化の要求により、排気温度が低温化する傾向にあるため、排気ガス浄化触媒に関してはＣＯ酸化活性が下がる懸念があった。中でも、高価な貴金属の含有量を減らしてパラジウム（Ｐｄ）を使用し、且つ、下層にＰｄを担持させる構成の３元系触媒においては、ＣＯの酸化活性をより一層高める必要があった。 Due to the recent demand for a reduction in CO 2 emission, the exhaust gas temperature tends to be lowered, and there has been a concern that the CO oxidation activity of the exhaust gas purification catalyst is lowered. In particular, a three-way catalyst having a structure in which palladium (Pd) is used while reducing the content of expensive noble metal and Pd is supported on the lower layer has to further increase the oxidation activity of CO.
そこで本発明は、触媒層を２層以上の複数構成とし、下層側にＰｄを担持させてなる構成を有する排ガス浄化触媒において、ＣＯの酸化活性をより一層高めることができる、新たな排ガス浄化触媒を提供せんとするものである。 Accordingly, the present invention provides a novel exhaust gas purification catalyst that can further enhance the oxidation activity of CO in an exhaust gas purification catalyst having a configuration in which the catalyst layer has a plurality of configurations of two or more layers and Pd is supported on the lower layer side. Is intended to provide.
本発明は、Ｐｄ、ＯＳＣ材及び無機多孔質体を含有する触媒層Ａと、Ｐｔ、Ｒｈ又はこれら両方、及び無機多孔質体を含有する触媒層Ｂと、を基材上に備え、前記触媒層Ａよりも上層側に前記触媒層Ｂを配置してなる構成を備えた触媒において、前記触媒層Ａは、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属を含有することを特徴とする排気ガス浄化触媒を提案する。 The present invention comprises a catalyst layer A containing Pd, an OSC material and an inorganic porous material, and a catalyst layer B containing Pt, Rh or both, and an inorganic porous material on a substrate, and the catalyst In the catalyst having a configuration in which the catalyst layer B is disposed on the upper side of the layer A, the catalyst layer A is one or more selected from the group consisting of Co, Ni, Mn, Cu and Fe. An exhaust gas purification catalyst characterized by containing a transition metal is proposed.
Ｐｄに対して、遷移金属、特にＣｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属を組み合わせて含有させることにより、一酸化炭素（ＣＯ）の浄化性能が良くなることが分かった。そこで本発明は、Ｐｄ、ＯＳＣ材及び無機多孔質体を含有する触媒層Ａと、Ｐｔ、Ｒｈ又はこれら両方、及び無機多孔質体を含有する触媒層Ｂとを備えた触媒において、触媒層ＡにＣｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属を含有させることにより、一酸化炭素（ＣＯ）の浄化性能を高めることに成功した。 By containing Pd in combination with a transition metal, particularly one or two or more transition metals selected from the group consisting of Co, Ni, Mn, Cu and Fe, carbon monoxide (CO) purification performance can be obtained. I found it to be better. Therefore, the present invention provides a catalyst layer A comprising a catalyst layer A containing Pd, an OSC material and an inorganic porous material, and a catalyst layer B containing Pt, Rh or both, and an inorganic porous material. By adding one or two or more transition metals selected from the group consisting of Co, Ni, Mn, Cu and Fe, the carbon monoxide (CO) purification performance was successfully improved.
次に、本発明を実施するための形態について説明する。但し、本発明が次に説明する実施形態に限定されるものではない。 Next, the form for implementing this invention is demonstrated. However, the present invention is not limited to the embodiment described below.
＜本触媒＞
本実施形態の一例に係る触媒（「本触媒」と称する）は、Ｐｄ、ＯＳＣ材及び無機多孔質体を含有する触媒層Ａと、Ｐｔ、Ｒｈ又はこれら両方、及び無機多孔質体を含有する触媒層Ｂとを備えた触媒であって、触媒層ＡにＣｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属を含有してなる排気ガス浄化触媒である。
<This catalyst>
The catalyst according to an example of this embodiment (referred to as “the present catalyst”) contains a catalyst layer A containing Pd, an OSC material and an inorganic porous material, Pt, Rh, or both, and an inorganic porous material. A catalyst provided with a catalyst layer B, wherein the catalyst layer A is an exhaust gas purification catalyst containing one or more transition metals selected from the group consisting of Co, Ni, Mn, Cu and Fe. .
「触媒層」とは、ガス吸着作用乃至ガス浄化触媒作用を有する層を意味し、触媒活性成分を含有していればガス浄化触媒作用を有するから該当する。 The “catalyst layer” means a layer having a gas adsorption action or a gas purification catalytic action, and corresponds to a gas purification catalytic action if it contains a catalytically active component.
＜触媒層Ａ＞
触媒層Ａは、触媒活性成分としてのＰｄと、遷移金属と、ＯＳＣ材と、無機多孔質体と、その他必要に応じた成分と、を含有する触媒層である。
触媒層Ａにおいて、Ｐｄと共に所定の遷移金属を組み合わせて含有させると、Ｐｄの分散度を高めることができると共に、Ｐｄ上に一酸化炭素（ＣＯ）が吸着され易くなり、一酸化炭素（ＣＯ）の浄化性能を高めることができる。
<Catalyst layer A>
The catalyst layer A is a catalyst layer containing Pd as a catalytically active component, a transition metal, an OSC material, an inorganic porous material, and other components as necessary.
In the catalyst layer A, when a predetermined transition metal is contained in combination with Pd, the dispersion degree of Pd can be increased, and carbon monoxide (CO) is easily adsorbed on Pd, and carbon monoxide (CO). Can improve the purification performance.
（触媒活性成分）
触媒層Ａは、触媒活性成分としてパラジウム（Ｐｄ）を主成分として含有していれば、他の触媒活性成分を含んでいてもよい。例えば白金、ロジウム、金、銀、ルテニウム、イリジウム、セリウム、オスミウム、ストロンチウム等のうちの一種又は２種以上の組み合わせを含んでいてもよい。
但し、触媒層Ａ中の触媒活性成分のうちの５０質量％以上、特に７０質量％以上、中でも特に９０質量％以上（１００質量％含む）をＰｄが占めるのが好ましい。
(Catalytic active ingredient)
The catalyst layer A may contain other catalytic active components as long as it contains palladium (Pd) as a catalytic active component as a main component. For example, one or a combination of two or more of platinum, rhodium, gold, silver, ruthenium, iridium, cerium, osmium, strontium and the like may be included.
However, it is preferable that Pd occupies 50% by mass or more, particularly 70% by mass or more, particularly 90% by mass or more (including 100% by mass) of the catalytically active component in the catalyst layer A.
（遷移金属）
触媒層Ａは、一酸化炭素（ＣＯ）の浄化性能を高める観点から、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属を含有するのが好ましい。中でも、一酸化炭素（ＣＯ）の浄化性能をより長期に渡って維持できる観点から、Ｃｏ、Ｎｉのうちの何れか或いは両方を含有するのが好ましい。触媒層Ａに含まれる遷移金属の状態は、金属、化合物、酸化物の何れであってもよい。
なお、これら触媒層Ａに含まれる遷移金属は、アルミナなどの無機多孔質体には担持されず、バインダーのように単独で存在しているものと推察される。
(Transition metal)
The catalyst layer A preferably contains one or more transition metals selected from the group consisting of Co, Ni, Mn, Cu and Fe from the viewpoint of improving the purification performance of carbon monoxide (CO). Among these, from the viewpoint of maintaining the carbon monoxide (CO) purification performance over a longer period, it is preferable to contain either or both of Co and Ni. The state of the transition metal contained in the catalyst layer A may be any of a metal, a compound, and an oxide.
In addition, it is guessed that the transition metal contained in these catalyst layers A is not carry | supported by inorganic porous bodies, such as an alumina, but exists independently like a binder.
これら遷移金属の含有量は、一酸化炭素（ＣＯ）の浄化性能を高める観点から、触媒層Ａに含まれるＰｄ１質量部に対して０．４〜１４．７質量部の割合で遷移金属を含有するのが好ましく、中でも３．３質量部以上の割合で、その中でも５．１質量部以上の割合で含有するのがさらに好ましい。 The content of these transition metals contains the transition metal at a ratio of 0.4 to 14.7 parts by mass with respect to 1 part by mass of Pd contained in the catalyst layer A from the viewpoint of enhancing the purification performance of carbon monoxide (CO). In particular, it is preferably 3.3 parts by mass or more, and more preferably 5.1 parts by mass or more.
（ＯＳＣ材）
触媒層Ａは、酸素ストレージ能（ＯＳＣ：Oxygen Storage capacity）を有する助触媒（「ＯＳＣ材」と称する）を含むのが好ましい。但し、無機多孔質体が、ＯＳＣ機能を有していれば。必ずしも必要ではない。
ＯＳＣ材としては、例えばセリウム化合物、ジルコニウム化合物、セリア・ジルコニア複合酸化物などを挙げることができる。
(OSC material)
The catalyst layer A preferably contains a promoter (referred to as “OSC material”) having oxygen storage capacity (OSC). However, if the inorganic porous body has an OSC function. It is not always necessary.
Examples of the OSC material include a cerium compound, a zirconium compound, and a ceria / zirconia composite oxide.
（無機多孔質体）
触媒層Ａは、触媒活性成分を担持する無機多孔質体として、例えばシリカ、アルミナおよびチタニア化合物から成る群から選択される化合物の多孔質体、より具体的には、例えばアルミナ、シリカ、シリカ−アルミナ、アルミノ−シリケート類、アルミナ−ジルコニア、アルミナ−クロミアおよびアルミナ−セリアから選択される化合物からなる多孔質体を含有するのが好ましい。
(Inorganic porous material)
The catalyst layer A is, for example, a porous body of a compound selected from the group consisting of silica, alumina and titania compounds, more specifically, for example, alumina, silica, silica- It is preferable to contain a porous body made of a compound selected from alumina, alumino-silicates, alumina-zirconia, alumina-chromia and alumina-ceria.
（その他の成分）
触媒層Ａは、必要に応じて、安定剤を含むのが好ましい。
安定剤としては、例えばアルカリ土類金属やアルカリ金属を挙げることができる。中でも、マグネシウム、バリウム、ホウ素、トリウム、ハフニウム、ケイ素、カルシウムおよびストロンチウムから成る群から選択される金属のうちの一種又は二種以上を選択可能である。その中でも、ＯＳＣ材及び無機多孔質体の耐熱性向上の観点から、バリウムが特に好ましい。
(Other ingredients)
The catalyst layer A preferably contains a stabilizer as necessary.
Examples of the stabilizer include alkaline earth metals and alkali metals. Of these, one or more metals selected from the group consisting of magnesium, barium, boron, thorium, hafnium, silicon, calcium, and strontium can be selected. Among these, barium is particularly preferable from the viewpoint of improving the heat resistance of the OSC material and the inorganic porous body.
触媒層Ａは、必要に応じて、バインダーを含むのが好ましい。
バインダー成分としては、無機系バインダー、例えばアルミナゾル等の水溶性溶液を使用することができる。
The catalyst layer A preferably contains a binder as necessary.
As the binder component, an inorganic binder such as an aqueous solution such as alumina sol can be used.
触媒層Ａは、必要に応じて他の成分を含有することができる。 The catalyst layer A can contain other components as necessary.
＜触媒層Ｂ＞
触媒層Ｂは、触媒活性成分としてのＰｔ、Ｒｈ又はこれら両方と、ＯＳＣ材と、無機多孔質体と、その他必要に応じた成分と、を含有する触媒層である。
<Catalyst layer B>
The catalyst layer B is a catalyst layer containing Pt, Rh or both as a catalyst active component, an OSC material, an inorganic porous material, and other components as required.
（触媒活性成分）
触媒層Ｂは、触媒活性成分として触媒活性成分としてのＰｔ、Ｒｈ又はこれら両方を主成分として含有していれば、他の触媒活性成分を含んでいてもよい。例えば金、銀、パラジウム、ルテニウム、イリジウム、ニッケル、セリウム、コバルト、銅、オスミウム、ストロンチウム、マンガン、鉄等のうちの一種又は２種以上の組み合わせを含んでいてもよい。
但し、触媒層Ａ中の触媒活性成分のうちの５０質量％以上、特に７０質量％以上、中でも特に９０質量％以上（１００質量％含む）を、触媒活性成分としてのＰｔ、Ｒｈ又はこれら両方が占めるのが好ましい。
(Catalytic active ingredient)
The catalyst layer B may contain other catalytic active components as long as it contains Pt, Rh, or both as catalytic active components as the catalytic active components. For example, one or a combination of two or more of gold, silver, palladium, ruthenium, iridium, nickel, cerium, cobalt, copper, osmium, strontium, manganese, iron, and the like may be included.
However, 50% by mass or more, particularly 70% by mass or more, particularly 90% by mass or more (including 100% by mass) of the catalytically active component in the catalyst layer A is contained as Pt, Rh or both as the catalytically active component. Preferably occupied.
（遷移金属）
Ｃｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅからなる群から選ばれる一種又は二種以上の遷移金属は、触媒層Ａに含まれていれば十分であるが、触媒層Ｂに含まれていてもよい。触媒層Ｂに含まれる遷移金属の状態は、金属、化合物、酸化物の何れであってもよい。
(Transition metal)
One or more transition metals selected from the group consisting of Co, Ni, Mn, Cu, and Fe are sufficient if they are contained in the catalyst layer A, but may be contained in the catalyst layer B. The state of the transition metal contained in the catalyst layer B may be any of a metal, a compound, and an oxide.
（ＯＳＣ材）
触媒層Ｂは、酸素ストレージ能（ＯＳＣ：Oxygen Storage capacity）を有する助触媒（ＯＳＣ材）を含むのが好ましい。但し、無機多孔質体が、ＯＳＣ機能を有していれば必ずしも必要ではない。
ＯＳＣ材としては、例えばセリウム化合物、ジルコニウム化合物、セリア・ジルコニア複合酸化物などを挙げることができる。
(OSC material)
The catalyst layer B preferably contains a promoter (OSC material) having oxygen storage capacity (OSC). However, it is not always necessary if the inorganic porous body has an OSC function.
Examples of the OSC material include a cerium compound, a zirconium compound, and a ceria / zirconia composite oxide.
（無機多孔質体）
触媒層Ｂは、触媒活性成分を担持する無機多孔質体として、例えばシリカ、アルミナおよびチタニア化合物から成る群から選択される化合物の多孔質体、より具体的には、例えばアルミナ、シリカ、シリカ−アルミナ、アルミノ−シリケート類、アルミナ−ジルコニア、アルミナ−クロミアおよびアルミナ−セリアから選択される化合物からなる多孔質体を含有するのが好ましい。
(Inorganic porous material)
The catalyst layer B is, for example, a porous body of a compound selected from the group consisting of silica, alumina and titania compounds, more specifically, for example, alumina, silica, silica- It is preferable to contain a porous body made of a compound selected from alumina, alumino-silicates, alumina-zirconia, alumina-chromia and alumina-ceria.
（その他の成分）
触媒層Ｂは、必要に応じて、安定剤を含むのが好ましい。
安定剤としては、例えばアルカリ土類金属やアルカリ金属を挙げることができる。中でも、マグネシウム、バリウム、ホウ素、トリウム、ハフニウム、ケイ素、カルシウムおよびストロンチウムから成る群から選択される金属のうちの一種又は二種以上を選択可能である。その中でも、ＯＳＣ材及び無機多孔質体の耐熱性向上の観点から、バリウムが特に好ましい。
(Other ingredients)
The catalyst layer B preferably contains a stabilizer as necessary.
Examples of the stabilizer include alkaline earth metals and alkali metals. Of these, one or more metals selected from the group consisting of magnesium, barium, boron, thorium, hafnium, silicon, calcium, and strontium can be selected. Among these, barium is particularly preferable from the viewpoint of improving the heat resistance of the OSC material and the inorganic porous body.
触媒層Ｂは、必要に応じて、バインダーを含むのが好ましい。
バインダー成分としては、無機系バインダー、例えばアルミナゾル等の水溶性溶液を使用することができる。
The catalyst layer B preferably contains a binder as necessary.
As the binder component, an inorganic binder such as an aqueous solution such as alumina sol can be used.
触媒層Ｂは、必要に応じて他の成分を含有することができる。 The catalyst layer B can contain other components as necessary.
なお、触媒層ＡとＢの接合性並びに製造コストなどの観点からすると、触媒活性成分の種類及び量以外は、触媒層Ａと共通とするのが好ましい。 From the viewpoint of the bonding properties of the catalyst layers A and B and the manufacturing cost, it is preferable to share the catalyst layer A with the exception of the type and amount of the catalytically active component.
＜本触媒の構成例＞
本触媒は、例えば基材上に上記触媒層Ａ及びＢを備え、前記触媒層Ａよりも上層側に前記触媒層Ｂを配置してなる構成を備えたものであるのが好ましい。
<Configuration example of this catalyst>
The present catalyst preferably has, for example, a structure in which the catalyst layers A and B are provided on a substrate, and the catalyst layer B is disposed on the upper side of the catalyst layer A.
かかる構成の触媒を作製するには、例えば触媒活性成分、遷移金属或いはその塩或いはその酸化物、無機多孔質体、ＯＳＣ材、安定化材、バインダー及び水を混合・撹拌してスラリーとし、得られたスラリーを例えばセラミックハニカム体などの基材にウオッシュコートし、これを焼成して、基材表面に触媒層Ａを形成した後、上記同様に上層(表面層)としての触媒層Ｂを形成すればよい。 In order to prepare a catalyst having such a configuration, for example, a catalyst active component, a transition metal or a salt or oxide thereof, an inorganic porous material, an OSC material, a stabilizing material, a binder and water are mixed and stirred to obtain a slurry. The obtained slurry is wash-coated on a base material such as a ceramic honeycomb body and fired to form a catalyst layer A on the surface of the base material, and then a catalyst layer B as an upper layer (surface layer) is formed in the same manner as described above. do it.
また、例えば遷移金属或いはその塩、無機多孔質体、ＯＳＣ材、安定化材、バインダー及び水を混合・撹拌してスラリーとし、得られたスラリーを例えばセラミックハニカム体などの基材にウオッシュコートした後、これを、触媒活性成分を含有する溶液に浸漬させて含浸させて基材表面に触媒層Ａを形成した後、上記同様に上層(表面層)としての触媒層Ｂを形成すればよい。 Further, for example, transition metals or salts thereof, inorganic porous bodies, OSC materials, stabilizing materials, binders and water are mixed and stirred to form a slurry, and the obtained slurry is wash coated on a substrate such as a ceramic honeycomb body. Thereafter, this is immersed in a solution containing a catalytically active component and impregnated to form the catalyst layer A on the surface of the substrate, and then the catalyst layer B as the upper layer (surface layer) may be formed in the same manner as described above.
この際、触媒層Ａと触媒層Ｂの間に、触媒層ではない層、例えば多孔質耐火性無機酸化物粉体からなる層や、多孔質耐火性無機酸化物粉体及び助触媒成分からなる層などの層が存在していてもよい。 At this time, a layer that is not a catalyst layer, for example, a layer made of porous refractory inorganic oxide powder, a porous refractory inorganic oxide powder, and a promoter component is formed between the catalyst layer A and the catalyst layer B. There may be a layer such as a layer.
触媒層Ａと触媒層Ｂの容量比率は０．５：１〜５：１であるのが好ましく、中でも０．５：１〜４：１、その中でも０．５：１〜３：１であるのが特に好ましい。
触媒層Ａと触媒層Ｂの厚み比率は０．２：１〜２０：１であるのが好ましく、中でも０．５：１〜１０：１、その中でも０．５：１〜５：１であるのが特に好ましい。
The volume ratio of the catalyst layer A and the catalyst layer B is preferably 0.5: 1 to 5: 1, more preferably 0.5: 1 to 4: 1, and more preferably 0.5: 1 to 3: 1. Is particularly preferred.
The thickness ratio of the catalyst layer A and the catalyst layer B is preferably 0.2: 1 to 20: 1, more preferably 0.5: 1 to 10: 1, and more preferably 0.5: 1 to 5: 1. Is particularly preferred.
（基材）
上記の基材の材質としては、セラミックス等の耐火性材料や金属材料を挙げることができる。セラミック製基材の材質としては、耐火性セラミック材料、例えばコージライト、コージライト−アルファアルミナ、窒化ケイ素、ジルコンムライト、スポジュメン、アルミナ−シリカマグネシア、ケイ酸ジルコン、シリマナイト（ｓｉｌｌｉｍａｎｉｔｅ）、ケイ酸マグネシウム、ジルコン、ペタライト（ｐｅｔａｌｉｔｅ）、アルファアルミナおよびアルミノシリケート類などを挙げることができる。金属製基材の材質としては、耐火性金属、例えばステンレス鋼または鉄を基とする他の適切な耐食性合金などを挙げることができる。
(Base material)
Examples of the material of the base material include refractory materials such as ceramics and metal materials. The material of the ceramic base material, refractory ceramic material, for example cordierite, cordierite - alpha alumina, silicon nitride, zircon mullite, spodumene, alumina - silica magnesia, zircon silicate, sillimanite (sillim a nite), silicate magnesium, zircon, petalite (pet a lite), and the like alpha alumina and aluminosilicates. The material of the metal substrate can include refractory metals such as other suitable corrosion resistant alloys based on stainless steel or iron.
基材の形状は、ハニカム状、ペレット状、球状を挙げることができる。
ハニカム材料としては、例えばセラミックス等のコージェライト質のものを用いることができる。また、フェライト系ステンレス等の金属材料からなるハニカムを用いることもできる。
ハニカム形状の基材を用いる場合、例えば基材内部を流体が流通するように、基材内部に平行で微細な気体流通路、すなわちチャンネルを多数有するモノリス型基材を使用することができる。この際、モノリス型基材の各チャンネル内壁表面に、触媒組成物をウォッシュコートなどによってコートして触媒層を形成することができる。
Examples of the shape of the substrate include a honeycomb shape, a pellet shape, and a spherical shape.
As the honeycomb material, for example, cordierite material such as ceramics can be used. A honeycomb made of a metal material such as ferritic stainless steel can also be used.
When a honeycomb-shaped substrate is used, for example, a monolith type substrate having a large number of parallel and fine gas flow passages, that is, channels, can be used so that fluid flows through the substrate. At this time, the catalyst layer can be formed by coating the inner wall surface of each channel of the monolith substrate with the catalyst composition by wash coating or the like.
本触媒はまた、排気ガスが流通する方向に触媒層Ｂ、触媒層Ａの順に配置してなる構成のものとすることもできる。
この際、触媒層Ａと触媒層Ｂの間に、触媒層ではない層、例えば多孔質耐火性無機酸化物粉体からなる層や、多孔質耐火性無機酸化物粉体及び助触媒成分からなる層などの層が存在していてもよい。
The present catalyst can also have a configuration in which the catalyst layer B and the catalyst layer A are arranged in this order in the direction in which the exhaust gas flows.
At this time, a layer that is not a catalyst layer, for example, a layer made of porous refractory inorganic oxide powder, a porous refractory inorganic oxide powder, and a promoter component is formed between the catalyst layer A and the catalyst layer B. There may be a layer such as a layer.
＜語句の説明＞
本明細書において「Ｘ〜Ｙ」（Ｘ，Ｙは任意の数字）と表現する場合、特にことわらない限り「Ｘ以上Ｙ以下」の意と共に、「好ましくはＸより大きい」或いは「好ましくはＹより小さい」の意も包含する。
また、「Ｘ以上」（Ｘは任意の数字）或いは「Ｙ以下」（Ｙは任意の数字）と表現した場合、「Ｘより大きいことが好ましい」或いは「Ｙ未満であることが好ましい」旨の意図も包含する。
<Explanation of words>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X is preferably greater than X” or “preferably Y”. It also includes the meaning of “smaller”.
In addition, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), it is “preferably greater than X” or “preferably less than Y”. Includes intentions.
以下、本発明を下記実施例及び比較例に基づいてさらに詳述する。 Hereinafter, the present invention will be described in more detail based on the following examples and comparative examples.
＜実施例１＞
硝酸Ｃｏを酸化物換算で７質量部と、多孔質γ-アルミナ４６質量部と、セリア・ジルコニア複合酸化物粒子粉末３０質量部と、無機系バインダーとしてのアルミナゾルを酸化物換算で１７質量部と、純水１００質量部とを秤量し、ボールミルにて混合を行うことでスラリーを得た。
Φ４０ｍｍ×Ｌ９０ｍｍ（３００セル）：担体容積０．１１３Ｌのステンレス製メタルハニカム基材を、前記スラリー中に浸漬し、引き上げて過剰なスラリーをエアーガンで吹き払った後、大気雰囲気下６００℃で３時間焼成してコート層を形成した。このとき、コート層の量はハニカム基材１Ｌ当り１００ｇであった。
このようにして得られたコート層付きハニカム基材を、硝酸Ｐｄ溶液中に浸漬させて余分な液滴をエアーガンで吹き払い、大気雰囲気下６００℃で３時間焼成して基材上に触媒層Ａを形成した。このとき、触媒層Ａの量はハニカム基材１Ｌに対して１５０ｇであり、Ｐｄの量はハニカム基材１Ｌに対し１．００ｇであった。
<Example 1>
7 parts by mass of Co nitrate in terms of oxide, 46 parts by mass of porous γ-alumina, 30 parts by mass of ceria / zirconia composite oxide particles, and 17 parts by mass of alumina sol as an inorganic binder in terms of oxides Then, 100 parts by mass of pure water was weighed and mixed with a ball mill to obtain a slurry.
Φ40 mm × L90 mm (300 cells): A stainless steel metal honeycomb substrate having a carrier volume of 0.113 L was immersed in the slurry, pulled up, and excess slurry was blown off with an air gun, and then at 600 ° C. for 3 hours in an air atmosphere. Firing was performed to form a coat layer. At this time, the amount of the coating layer was 100 g per 1 L of the honeycomb substrate.
The honeycomb substrate with the coat layer thus obtained was immersed in a Pd nitrate solution, excess droplets were blown off with an air gun, and fired at 600 ° C. for 3 hours in an air atmosphere to lay the catalyst layer on the substrate. A was formed. At this time, the amount of the catalyst layer A was 150 g with respect to 1 L of the honeycomb substrate, and the amount of Pd was 1.00 g with respect to 1 L of the honeycomb substrate.
次に、多孔質γ-アルミナ５３質量部と、セリア・ジルコニア複合酸化物粒子粉末３０質量部と、無機系バインダーとしてのアルミナゾルを酸化物換算で１７質量部と、純水１００質量部とを秤量し、ボールミルにて混合を行うことでスラリーを得た。
前記触媒層Ａを形成した基材を、該スラリー中に浸漬し、引き上げて過剰なスラリーをエアーガンで吹き払った後、大気雰囲気下６００℃で３時間焼成してコート層を形成した。このとき、コート層の量はハニカム基材１Ｌ当り１００gであった。
このようにして得られたコート層付きハニカム基材を、硝酸Ｐｔ・Ｒｈ溶液中に浸漬させて余分な液滴をエアーガンで吹き払い、大気雰囲気下６００℃で３時間焼成して触媒層Ｂを形成して、基材上に触媒層Ａ，Ｂを備えた排ガス浄化触媒（サンプル）を得た。
このとき、触媒層Ｂの量はハニカム基材１Ｌに対して１００gであり、Ｐｔ及びＲｈの量はハニカム基材１Ｌに対し０．１０ｇであった。
Next, 53 parts by mass of porous γ-alumina, 30 parts by mass of ceria / zirconia composite oxide particle powder, 17 parts by mass of alumina sol as an inorganic binder in terms of oxide, and 100 parts by mass of pure water are weighed. The slurry was obtained by mixing with a ball mill.
The base material on which the catalyst layer A was formed was immersed in the slurry, pulled up, and excess slurry was blown off with an air gun, and then fired at 600 ° C. for 3 hours in an air atmosphere to form a coat layer. At this time, the amount of the coating layer was 100 g per 1 L of the honeycomb substrate.
The honeycomb substrate with the coating layer thus obtained was immersed in a Pt / Rh nitric acid solution, excess droplets were blown off with an air gun, and the catalyst layer B was fired at 600 ° C. for 3 hours in an air atmosphere. An exhaust gas purification catalyst (sample) having catalyst layers A and B on the substrate was obtained.
At this time, the amount of the catalyst layer B was 100 g with respect to 1 L of the honeycomb substrate, and the amounts of Pt and Rh were 0.10 g with respect to 1 L of the honeycomb substrate.
＜実施例２＞
触媒層Ａと同様の割合で、触媒層Ｂを形成するためのスラリーに硝酸Ｃｏを配合した以外の点は実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 2>
An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Co nitrate was added to the slurry for forming the catalyst layer B at the same ratio as the catalyst layer A.
＜実施例３＞
硝酸Ｃｏの代わりに、硝酸Ｎｉを配合した以外の点は実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 3>
An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Ni nitrate was added instead of Co nitrate.
＜実施例４＞
硝酸Ｃｏの代わりに、硝酸Ｍｎを配合した以外の点は実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 4>
An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Mn nitrate was added instead of Co nitrate.
＜実施例５＞
硝酸Ｃｏの代わりに、硝酸Ｃｕを配合した以外の点は実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 5>
An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Cu nitrate was added instead of Co nitrate.
＜実施例６＞
硝酸Ｃｏの代わりに、硝酸Ｆｅを配合した以外の点は実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 6>
An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Fe nitrate was added instead of Co nitrate.
＜実施例７＞
実施例１において、コート層付きハニカム基材を硝酸Ｐｄ溶液中に浸漬させる代わりに、硝酸Ｐｄ・Ｐｔ溶液に浸漬させて基材上に触媒層Ａを形成すると共に、コート層付きハニカム基材を硝酸Ｐｔ・Ｒｈ溶液中に浸漬させる代わりに、硝酸Ｒｈ溶液に浸漬させて触媒層Ｂを形成した以外の点は、実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 7>
In Example 1, instead of immersing the honeycomb substrate with the coat layer in the Pd nitrate solution, the catalyst layer A was formed on the substrate by immersing it in the Pd / Pt nitrate solution. An exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that the catalyst layer B was formed by immersing in the nitric acid Rh solution instead of immersing in the nitric acid Pt / Rh solution.
＜実施例８−１３＞
触媒層Ａの形成において、硝酸Ｃｏの配合量を変更して、Ｐｄに対するＣｏを表４に示すように調整した以外の点は、実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Example 8-13>
In the formation of the catalyst layer A, an exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that the blending amount of Co nitrate was changed and Co with respect to Pd was adjusted as shown in Table 4.
＜比較例１＞
触媒層Ａの形成において、硝酸Ｃｏを配合しなかった以外の点は、実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Comparative Example 1>
In the formation of the catalyst layer A, an exhaust gas purification catalyst (sample) was prepared in the same manner as in Example 1 except that Co nitrate was not blended.
＜比較例２＞
触媒層Ａの形成において、硝酸Ｃｏに浸漬させず、実施例１の触媒層Ａと同様の割合で、触媒層Ｂを形成するためのスラリーに硝酸Ｃｏを配合した以外の点は、実施例１と同様に排ガス浄化触媒（サンプル）を作製した。
<Comparative Example 2>
Example 1 is the same as Example 1 except that Co nitrate was not mixed with Co nitrate and the slurry for forming the catalyst layer B was blended in the same ratio as that of Example 1 in the formation of the catalyst layer A. Similarly, an exhaust gas purification catalyst (sample) was prepared.
なお、表中のＰｄ量、Ｒｈ量、ＣｅＯ2量などは、製造時の配合量を示したものであるが、触媒を製造後に測定した場合の含有量と同じ値である（他の実施例・比較例についても同様）。 The Pd amount, Rh amount, CeO 2 amount, etc. in the table indicate the blending amount at the time of production, and are the same values as the content when the catalyst is measured after production (other examples)・ The same applies to the comparative example).
＜浄化性能評価方法（Ｔ５０-ＣＯ）＞
次の表１に示す模擬排気ガス（Fresh）を、実施例１〜７、比較例１〜２で得た排ガス浄化触媒（サンプル）に流通させ、１００℃〜５００℃における出口ガス成分をＣＯ分析計を用いて測定した。得られた測定結果より、５０％浄化率に到達する温度（Ｆｒｅｓｈ
ＣＯ:Ｔ５０（℃））を求めた。
<Purification performance evaluation method (T50-CO)>
The simulated exhaust gas (Fresh) shown in the following Table 1 is circulated through the exhaust gas purification catalyst (sample) obtained in Examples 1 to 7 and Comparative Examples 1 and 2, and the outlet gas component at 100 ° C. to 500 ° C. is subjected to CO analysis. Measured using a meter. From the obtained measurement results, the temperature (Fresh) that reaches the 50% purification rate
CO: T50 (° C.)).
（考察）
触媒層Ａにおいて、Ｐｄに対して、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｕ及びＦｅなどの遷移金属を組み合わせて含有させることにより、一酸化炭素（ＣＯ）の浄化性能が良くなることが分かった。中でも、Ｐｄに対してＣｏ又はＮｉを組み合わせて含有させると、一酸化炭素（ＣＯ）浄化性能がより一層良好となることが分かった。また、Ｐｔは、触媒層Ａ、Ｂのどちらに含有されていてもよいことが分かった。
(Discussion)
In the catalyst layer A, it was found that the purification performance of carbon monoxide (CO) is improved by containing Pd in combination with transition metals such as Co, Ni, Mn, Cu and Fe. In particular, it has been found that when Co or Ni is contained in combination with Pd, the carbon monoxide (CO) purification performance is further improved. Moreover, it turned out that Pt may be contained in any of the catalyst layers A and B.
＜浄化性能評価方法（車両評価）＞
実施例２、実施例８〜１３及び比較例１で得た排ガス浄化触媒（サンプル）を２輪車へ組み込み、ＥｕｒｏIIIモードでのＣＯガス排出量を、ＣＯ分析計を用いて測定した（Ｆｒｅｓｈ ＣＯ:ＣＯ排出量）。
また、実施例２、実施例８〜１３及び比較例１で得た排ガス浄化触媒（サンプル）を、表３に示す条件で耐久試験を行った後（Aged）、ＥｕｒｏIIIモードでのＣＯガス排出量（Ａｇｅｄ ＣＯ:ＣＯ排出量）を上記同様に求めた。なお、ＣＯ排出量は比較例１を１００％としたときの相対排出量で示した。
<Purification performance evaluation method (vehicle evaluation)>
The exhaust gas purification catalyst (sample) obtained in Example 2, Examples 8 to 13 and Comparative Example 1 was incorporated into a two-wheeled vehicle, and the CO gas emission amount in the Euro III mode was measured using a CO analyzer (Fresh CO : CO emissions).
Further, after exhaust gas purification catalysts (samples) obtained in Example 2, Examples 8 to 13 and Comparative Example 1 were subjected to an endurance test under the conditions shown in Table 3 (Aged), CO gas emissions in the EuroIII mode (Aged CO: CO emission amount) was determined in the same manner as described above. In addition, CO discharge amount was shown by the relative discharge amount when the comparative example 1 was set to 100%.
（考察）
遷移金属は、一酸化炭素（ＣＯ）の浄化性能を高める観点から、Ｐｄ１質量部に対して０．４〜１４．７質量部の割合で配合するのが好ましく、中でもFreshの一酸化炭素（ＣＯ）の浄化性能を高める観点から、３．３質量部以上或いは１４．７質量部以下、その中でも５．１質量部以上或いは１４．７質量部以下の割合で配合するのが好ましいと考えることができる。
(Discussion)
From the viewpoint of improving the purification performance of carbon monoxide (CO), the transition metal is preferably blended at a ratio of 0.4 to 14.7 parts by mass with respect to 1 part by mass of Pd. Among them, fresh carbon monoxide (CO From the viewpoint of improving the purification performance of (3), it is considered that it is preferable to blend at a ratio of 3.3 parts by mass or more and 14.7 parts by mass or less, and among them, 5.1 parts by mass or more and 14.7 parts by mass or less. it can.
Claims (5)
前記触媒層Ａにおいて、Ｃｏは金属コバルト又は酸化コバルトの状態で含有され、且つ、Ｐｄ１質量部に対して０．４〜７．３質量部の割合でＣｏを含有することを特徴とする排気ガス浄化触媒（但し、前記触媒層Ａがペロブスカイト型複合酸化物を構成する金属としてのみＣｏを含有する触媒は除く）。 A catalyst layer A containing Pd, OSC material, inorganic porous material, and Co, and a catalyst layer B containing Pt, Rh, or both, and an inorganic porous material are provided on a substrate, and the catalyst layer A Comprising a structure in which the catalyst layer B is disposed on the upper layer side,
In the catalyst layer A, Co is contained in a state of metallic cobalt or cobalt oxide , and contains Co at a ratio of 0.4 to 7.3 parts by mass with respect to 1 part by mass of Pd. Purification catalyst (excluding a catalyst in which the catalyst layer A contains Co only as a metal constituting the perovskite complex oxide).
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